feat!: read code coverage config from Cypress.expose instead of Cypress.env

[cacieprins]

BREAKING CHANGE: @cypress/code-coverage configuration must now be placed under expose instead of env in your Cypress configuration.

Migrate from Cypress.env() to Cypress.expose()

This PR migrates @cypress/code-coverage's configuration from Cypress.env() to Cypress.expose() in response to the deprecation of Cypress.env() in Cypress v15.10.0. Cypress.env() will be removed in Cypress 16, necessitating this breaking change. For more details about why Cypress has deprecated Cypress.env(), see the official documentation on migrating from Cypress.env() to Cypress.expose().

What Changed

• Configuration location: This plugin is now configured via the expose key in your Cypress configuration, rather than the env key.
• API access: All internal references to Cypress.env() replaced with Cypress.expose()

Migration

Before:

// cypress.config.js
const { defineConfig } = require('cypress')

module.exports = defineConfig({
  env: {
    codeCoverage: {
      url: 'http://localhost:3000/__coverage__',
      exclude: ['cypress/**/*.*'],
      expectBackendCoverageOnly: true
    },
    sendCoverageBatchSize: 1000,
    coverage: false
  }
})

After:

// cypress.config.js
const { defineConfig } = require('cypress')

module.exports = defineConfig({
  expose: {
    codeCoverage: {
      url: 'http://localhost:3000/__coverage__',
      exclude: ['cypress/**/*.*'],
      expectBackendCoverageOnly: true
    },
    sendCoverageBatchSize: 1000,
    coverage: false
  }
})

CLI usage:

# Before
cypress run --env coverage=false

# After
cypress run --expose coverage=false

Additional Changes

• TypeScript migration: Codebase migrated from JavaScript to TypeScript (see refactor: migrates to typescript #975)
• Test infrastructure: Unit tests migrated from Cypress e2e tests to Vitest (see tests: migrate unit tests from Cypress e2e style tests to vitest #974)
• Documentation: Updated README with migration guide and all configuration examples
• Test apps: All test applications updated to use new configuration format
• Dependencies: Updated to require Cypress >=15.10.0 and Node >=20

Impact

• Breaking: Existing configurations using env.codeCoverage will no longer work
• Compatibility: Requires Cypress >=15.10.0. Requires Node >=20.
• Migration path: Clear migration guide provided in README

See the migration guide in the README for detailed migration instructions.

---

Note

High Risk
Breaking API change that affects all consumers’ Cypress configuration and touches core coverage collection/reporting paths; incorrect expose setup could silently disable coverage or alter reporting behavior.

Overview
Breaking change: @cypress/code-coverage now reads all runtime configuration (including codeCoverage, coverage, and sendCoverageBatchSize) from Cypress.expose() / config.expose instead of Cypress.env() / config.env, and sets the codeCoverageTasksRegistered flag via config.expose.

The plugin implementation is refactored to TypeScript across core modules (lib/task, lib/task-utils, lib/common-utils) and middleware, adds a shared lib/plugins.ts entrypoint, and updates backend coverage middleware to return null when coverage is unavailable.

Test/CI plumbing is updated: CircleCI moves to newer Cypress orb and Node images, adds a build-dist step gating matrix test-app verification and Windows runs, and repository Cypress e2e test scaffolding is removed in favor of the new unit-test setup; docs and example configs are updated to use expose (including a new 3.x→4.x migration section), and test-apps/*/package-lock.json is gitignored.

^{Written by Cursor Bugbot for commit 2455c9b. This will update automatically on new commits. Configure here.}

[mschile]

Searching for 'env' shows other mentions of 'env' that we probably want to update as well.

[mschile]

Added a couple comments.

[cacieprins]

@cursor review

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{Bugbot Autofix is OFF. To automatically fix reported issues with Cloud Agents, enable Autofix in the Cursor dashboard.}

[cypress-app-bot]

🎉 This PR is included in version 4.0.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀